Plasma endothelin levels and outcome in patients undergoing repair of ruptured infrarenal abdominal aortic aneurysm

Background: Endothelin-1 (ET-1) is the most potent known vasoconstrictor. Elevated plasma levels have been demonstrated in patients with myocardial infarction, cardiogenic and septic shock, and respiratory, heart, and kidney failure, as well as in those undergoing elective abdominal aortic aneurysm (AAA) repair. However, endothelin levels have not previously been examined in patients undergoing repair of ruptured AAA. We hypothesized that hemorrhagic shock, lower torso ischemia, and reperfusion associated with ruptured AAA repair lead to increased synthesis and secretion of ET-1, which, in turn, predispose to organ failure, one of the principal causes of death in this condition. Methods: Fourteen patients were studied. Plasma levels of big ET-1 and ET-1 were measured immediately before operation and immediately before, 5 minutes, and 6 hours after aortic clamp release. Results: All patients survived for at least 24 hours after operation. Big ET-1 levels were above the normal range at one or more sample points in all patients, and the ET-1 levels were above the normal range in all survivors and four of five nonsurvivors. Five patients who died of organ failure had significantly lower big ET-1 levels at all sample points and significantly lower ET-1 levels after 5 minutes of reperfusion when compared with survivors. Preoperative ET-1 levels were significantly lower in eight patients who subsequently developed kidney failure than in six patients who did not. Conclusion: Contrary to our original hypothesis, these novel data demonstrate that patients with ruptured AAA in whom fatal postoperative organ failure develops have significantly lower perioperative endothelin levels than survivors.